It is known in the prior art that wound closure requires that the epithelial and subcutaneous tissues adjacent the wound migrate toward the wound. Unfortunately, in the case of large or infected wounds, often the result of chronic disease or pressure sores, spontaneous closure does not take place. In these cases, localized swelling forms near the surface of the wound restricting flow of blood. As a result of this diminished blood flow the wound is unable to successfully fight bacterial infection. The resulting increased infection causes further restriction of blood flow, which in turn results in further diminished blood flow and so forth, ultimately leading to the necessity for radical intervention. In many cases the patient requires hospitalization for drug administration and/or surgical treatment.
The application of continuous negative pressure has been shown to contribute significantly to wound closure. Such applications typically involve the insertion of an open cell foam pad into a wound region. The pad is then covered with a polymer sheet to seal the region from atmosphere. Thereafter, negative pressure is applied to the wound site through a tube having one end inserted into the interior of the foam pad and the opposite end attached to a vacuum pump via an interposed chamber for collection of wound fluids. Clinical results demonstrate that such applications of negative pressure promote the migration of epithelial and subcutaneous tissue toward the wound while serving to evacuate wound exudates and reduce bacterial density.
Unfortunately, the application of continuous negative pressure makes difficult the administration of topical disinfectant drugs and control of the local atmospheric content and does little to promote drying of the wound area. It is therefore desired to achieve infection control in a manner that promotes the application of topical disinfectants while allowing the caregiver to adjust the local atmospheric condition, including content and temperature. The removal of wound fluids through continuous negative pressure also suffers the disadvantage of requiring strict infection control. This is most often accomplished through the provision of very expensive hydrophobic filters between the collection canister and vacuum pump and other safety measures. It is therefore desirable to eliminate the necessity for such expensive apparatuses while still providing a safe and effective means for the removal of wound exudates.
In accordance with the foregoing objects, the present invention—a method and apparatus for wound treatment—generally comprises a polyurethane or polyether foam pad, adapted for insertion substantially within a wound cavity; a pump for supplying fluid flow to the wound site; and a collection canister for receiving wound fluids drawn from the wound cavity. The foam pad, pump and collection canister are in fluid communication with one another through a single hospital grade hose having a plurality of tiny apertures in the portion that is central to the foam pad. These apertures are adapted to allow fluids from the wound cavity to be drawn into the flow from the pump to the canister according to Bernoulli's theorem, which states generally that the work done on a fluid is equal to the change in kinetic energy of the fluid.
Many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims.